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Coronal Density Measurements Using Giant Radio Pulses of the Crab Pulsar at the Cycle 24/25 Minimum

Tokumaru, Munetoshi; Terasawa, Toshio; Takefuji, Kazuhiro +2 more

Accurate measurements of the coronal plasma density profile, which varies with the solar cycle (SC), are necessary to elucidate the solar wind acceleration. In this study, the Crab pulsar is observed using the 327 MHz radio telescope at the Toyokawa Observatory of the Institute for Space-Earth Environmental Research of Nagoya University to investi…

Formation and Immediate Deformation of a Small Filament Through Intermittent Magnetic Interactions

Zhang, Liang; Chen, Yao; Zheng, Ruisheng +4 more

It is generally believed that filament formation involves a process of the accumulation of magnetic energy. However, in this article, we discuss the idea that filaments will not erupt and will only deform when the stored magnetic energy is released gradually. Combining high-quality observations from SolarDynamicsObservatory and other instruments, …

Correction to: Observation of a Flare and Filament Eruption in Lyman-α on 8 September 2011 by the PRoject for OnBoard Autonomy/Large Yield Radiometer (PROBA2/LYRA)

Kretzschmar, M.; Dammasch, I. E.; Dominique, M. +3 more

Critical Science Plan for the Daniel K. Inouye Solar Telescope (DKIST)

Andretta, Vincenzo; Ayres, Thomas R.; Liu, Wei +87 more

The National Science Foundation's Daniel K. Inouye Solar Telescope (DKIST) will revolutionize our ability to measure, understand, and model the basic physical processes that control the structure and dynamics of the Sun and its atmosphere. The first-light DKIST images, released publicly on 29 January 2020, only hint at the extraordinary capabiliti…

A New View of the Solar Interface Region from the Interface Region Imaging Spectrograph (IRIS)

Reeves, Katharine K.; Polito, Vanessa; Liu, Wei +11 more

The Interface Region Imaging Spectrograph (IRIS) has been obtaining near- and far-ultraviolet images and spectra of the solar atmosphere since July 2013. IRIS is the highest resolution observatory to provide seamless coverage of spectra and images from the photosphere into the low corona. The unique combination of near- and far-ultraviolet spectra…

Upflows in the Upper Solar Atmosphere

Tian, Hui; Brooks, David H.; Baker, Deborah +2 more

Spectroscopic observations at extreme- and far-ultraviolet wavelengths have revealed systematic upflows in the solar transition region and corona. These upflows are best seen in the network structures of the quiet Sun and coronal holes, boundaries of active regions, and dimming regions associated with coronal mass ejections. They have been intensi…

Probabilistic Drag-Based Ensemble Model (DBEM) Evaluation for Heliospheric Propagation of CMEs

Veronig, Astrid M.; Dumbović, Mateja; Temmer, Manuela +4 more

The Drag-based Model (DBM) is a 2D analytical model for heliospheric propagation of Coronal Mass Ejections (CMEs) in ecliptic plane predicting the CME arrival time and speed at Earth or any other given target in the solar system. It is based on the equation of motion and depends on initial CME parameters, background solar wind speed, w and the dra…

Assessing the Predictability of Solar Energetic Particles with the Use of Machine Learning Techniques

Lavasa, E.; Giannopoulos, G.; Papaioannou, A. +5 more

A consistent approach for the inherently imbalanced problem of solar energetic particle (SEP) events binary prediction is being presented. This is based on solar flare and coronal mass ejection (CME) data and combinations of both thereof. We exploit several machine learning (ML) and conventional statistics techniques to predict SEPs. The methods u…

Role of Compressive Viscosity and Thermal Conductivity on the Damping of Slow Waves in Coronal Loops with and Without Heating-Cooling Imbalance

Srivastava, A. K.; Wang, T. J.; Prasad, Abhinav

In the present article, we derive a new dispersion relation for slow magnetoacoustic waves invoking the effect of thermal conductivity, compressive viscosity, radiation, and an unknown heating term along with the consideration of heating-cooling imbalance from linearized MHD equations. We solve the general dispersion relation to understand the rol…

Measurements of Solar Differential Rotation Using the Century Long Kodaikanal Sunspot Data

Chatterjee, Subhamoy; Banerjee, Dipankar; Jha, Bibhuti Kumar +2 more

The rotational profile of the Sun is considered to be one of the key inputs in a solar dynamo model. Hence, precise and long-term measurements of this quantity is important for our understanding of solar magnetism and its variability. In this study, we use the newly digitised, white-light sunspot data (1923 - 2011) from Kodaikanal Solar Observator…